From the prior art various transmission shifting devices are known, which serve both to actuate a parking lock and to change the shift position of a transmission. For example, DE 102004 052 869 A1 describes a parking lock mechanism for a transmission. The known parking lock mechanism comprises a gearshift lever whose pivoting movement is transferred, via a shaft, to a detent lever. At its periphery the detent lever has teeth in which a detent spring can engage. To the detent lever is also articulated a parking rod, which can be pushed in the longitudinal direction by pivoting the detent lever. At the end of the parking rod is a cam which, when the detent lever is in the corresponding position, acts upon a parking pawl which then locks the transmission.
A similar device is also disclosed in DE 196 30 806 A1, where a selector shaft actuated by a selector level is described, a detent disk being provided which is connected rotationally fixed to the selector shaft. To lock the detent disk a positioning element is provided, which slides over outer teeth of the detent disk and can engage in the tooth gaps. To move past the dead point at the peak of an individual tooth a roller is provided on the detent disk, which projects outward above the tooth and over which the positioning element can roll.
In contrast to the prior art mentioned above DE 197 44 238 A1 describes a mechanism which serves not only to activate a parking lock but also to adjust the shift position of a transmission. This known mechanism comprises a shift lever connected in a rotationally fixed manner to a manual control lever. In turn, on the manual control lever is arranged in a rotationally fixed manner a plate component, which is provided along a circumferential section with teeth in which a locking spring can engage. In the plate component is provided a slot, which extends in the circumferential direction of the plate component and has a shape that deviates from a straight line. Opposite the plate component there is a so-termed reaction support, which is also plate-shaped and is fixed to the housing of the device. A slot is also provided in the reaction support. The known mechanism comprises in addition a rod, one end of which projects into the slots in the plate component and the reaction support, while its other end is connected to a transmission valve of the transmission. When the plate component rotates, the one end of the rod follows the irregular path within the slot in the plate component and causes the transmission valve to move one way or the other. Rotating the plate component changes the position of the transmission valve and thus also the shift position of the transmission. The function of the slot in the reaction support is to restrict the degree of freedom of the rod's movement.
However, the known mechanism has certain disadvantages. For one thing, the rotating plate component must be made very large to accommodate the slot extending in its circumferential direction. Consequently the known mechanism takes up a large structural space. For another thing, the known mechanism is not so easy to adapt to different vehicle shift systems.